The present invention relates to explosion-proof apparatuses and more particularly to V-band couplings for use in holding together explosion-proof enclosures or other pressure vessels which have circular flange joints.
Explosion-proof enclosures are intended for use in hazardous environments where flammable gases or vapors may be present. These enclosures are designed to contain internal explosions without causing any external hazard. The enclosures must therefore be sufficiently strong to avoid fracture or rupture and must have sufficiently tight shaft and flange tolerances to insure that any hot gases resulting from an explosion will be cooled as they attempt to exit the enclosure.
Explosion-proof enclosures have frequently been designed using the brute strength approach whereby a cover is attached to a base through the use of multiple bolts which are time consuming to remove when accessing the interior of the enclosure. As an alternative V-band couplings have been employed to secure separate halves or sections of explosion-proof enclosures together which allow for much more convenient access into the interiors of the enclosures and smaller enclosure dimensions due to reduced flange size. However, it has heretofore been difficult to provide an explosion-proof enclosure secured by a V-band coupling having the same ability to withstand the high pressures of internal explosions since V-band couplings have had a tendency to slide off of the flanges of the enclosures which they hold together as their trunnion joints fail due to high levels of tensile or hoop stress. V-band couplings can be made to be very robust in order resist the stresses involved but his requires awkward and bulky components which are also costly to produce.
It is therefore an object of the present invention to provide an improved V-band coupling for holding together the halves or sections of an explosion-proof enclosure which enables the enclosure assembly to have greater ability to withstand internal explosions.
It is a further object of the present invention to provide a V-band for an explosion-proof enclosure featuring a higher coefficient of friction with the enclosure flanges which it engages in order to reduce the amount of hoop stress and trunnion load resulting from internal explosions in such enclosures.
It is yet another object of the present invention to provide an improved V-band coupling for use on an explosion-proof enclosure which is cost effective to manufacture and is reliable in operation.